The field of the invention relates generally to power converters, and more specifically, to a system and method for commutating of power bridges for which switching is highly-constrained in time to the desired output waveform.
Improvement of control convergence in power converters benefits from a minimization of the latency between measurement and the discrete opportunities for enforcement. At least some known power converter commutation circuits rely on past performance of the bridge to determine future switching times. Such circuits and methods are inaccurate in high frequency applications where relatively slower switching components are used. Additionally, such schemes do not account for disturbance signals that may be present while maintaining high efficiency.
Known machine control typically applies a voltage that emulates a phasor with a constant magnitude and frequency for bandwidths beyond that of the current regulator (or other primary regulator). Even in steady-state, switched-mode power supplies produce predictable errors in voltage and volt-seconds, and in both radial and circumferential axes. Further, transient bandwidth typically suffers from traditional approaches to reduce these errors, particularly when applied to power bridges with significant limitations in net switching frequency.
Methods of gating a highly-constrained power bridge typically involve very low chopping frequencies or pattern firing. Low chopping frequencies tend to constrain the maximum fundamental frequency of the applied waveform. Pattern firing techniques tend to limit the responsiveness of outer regulators.